1. Field of the Invention
The present invention relates to a parallel data transfer system for transferring data from an electronic device to a host computer via a connection cable, and relates to the electronic device employed in the parallel data transfer system.
2. Description of the Related Art
Generally, in parallel data transfer systems, an electronic device is connected to a host computer via a connection cable. In response to a transfer instruction signal transmitted from the host computer, the electronic device transfers data in parallel to the host computer.
In one example of the parallel data transfer system, an image scanner is connected via a connection cable to a host computer. The image scanner is provided with a reading mechanism for optically reading image information from an original and for producing image data. The image scanner is provided with a transmission/reception circuit which includes a Centronics communication port to which a Centronics connector is connected for connecting to the connection cable. The Centronics communication port and the Centronics connector are for transmitting and receiving parallel data to and from an external device. The image scanner can therefore transmit image data in parallel form to the host computer via the connection cable.
The host computer is constructed from a personal computer, for example. The host computer is also provided with a transmission/reception circuit which includes a Centronics communication port to which is connected a Centronics connector for connecting to the connection cable. The host computer can therefore receive the parallel image data transmitted via the connection cable from the image scanner. The host computer is constructed to be capable of transmitting the received image data to a printer device such as a laser printer. The host computer can produce image data by itself and can transmit the image data to the printer device.
There has been recently realized one type of Centronics communication system which transmits parallel data according to an IEEE1284 parallel communication interface standard. The IEEE1284 parallel communication interface is established by the Institute of Electrical and Electronics Engineers (IEEE).